"Collapsible Dropdown Listbox" as button with listbox?

[JAWS-test]

Regarding https://w3c.github.io/aria-practices/examples/listbox/listbox-collapsible.html

It seems very strange to me that the ARIA alternative to select size=1 has been implemented as a button that opens a list box. select size=1 should be output as a combobox according to the specification. I personally think it would be better: as listbox (w3c/html-aam#230). Be that as it may: a button is wrong. Example: In JAWS all combo boxes and list boxes can be listed with INS+CTRL+C: The button will then not be displayed.

Another problem is that form fields have a label and a value that are output separately. A button has only a label and no value. The example includes the value in the label. However, this leads to an incorrect output by the screen reader.

My suggestion: Remove the example and revise it.

See also: #657

[JAWS-test]

Another problem is that the element cannot be marked as incorrect or required (aria-required, aria-invalid, aria-errormessage are not allowed)

See also w3c/aria#1253